Bone alignment implant and method of use

ABSTRACT

A bone alignment implant includes a first bone fastener with a first bone engager that is adapted for fixation into the metaphyseal bone and a second bone fastener with a second bone engager that is adapted for fixation into the metaphyseal bone. A link connecting the two fasteners spans across the physis. These implants act as a flexible tethers between the epiphyseal and the metaphyseal sections of bone during bone growth. These implants are designed to adjust and deform during the bone realignment process. When placed on the convex side of the deformity, the implant allows the bone on the concave side of the deformity to grow. During the growth process the bone is then realigned. A similar procedure is used to correct torsional deformities.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

BACKGROUND OF THE INVENTION

1. The Field of the Invention

The present invention relates to the design and method of use for animplant to help realign angular and rotational deformities in long bonesin patients with active growth plates.

2. Related Technology

As a result of congenital deformation, traumatic injury or other causes,long bones such as the femur, tibia and humerus may grow out ofalignment, causing deformity of the limb and biomechanicalabnormalities. While some deformities are asymptomatic or may resolvespontaneously, it is often necessary to intervene surgically to realignthese limbs. For the patients requiring surgical intervention, bothosteotomy with realignment of the bone and epiphyseal stapling arecurrently accepted methods of treatment.

One common method of surgical bone realignment is by means of anosteotomy, or cutting of the bone, followed by realignment of the bone.In some procedures the bone is cut laterally, transverse to thelongitudinal axis of the bone. Then the bone is realigned. A bone graftis then placed in the resulting wedge space. The bone and the bone graftare stabilized by orthopedic fragment fixation implants such as screwsand bone plates. In an alternative osteotomy procedure, a bone wedge isremoved. The bone is realigned, and similar implants are used to securethe bone. A third method of deformity correction via osteotomy is tofirst cut the bore, then apply an external frame attached to pinsdrilled through the skin and into the bone. By adjusting the frame,either intraoperatively or postoperatively, the bone is straightened.

Because osteotomy methods require a relatively large incision to createbone cuts, they are relatively invasive; they disrupt the adjacentmusculature and may pose a risk to the neurovascular structures. Anadditional disadvantage of these procedures is the potential risk ofdamage to the growth plate, resulting in the disruption of healthy limbgrowth. Consequently, this procedure may be reserved for bone alignmentin skeletally mature patients in whom the growth plates are no longeractive.

One less invasive method of bone alignment involves the placement ofconstraining implants such as staples around the growth plate of thebone to restrict bone growth at the implant site and allow the bone togrow on the opposite side. First conceived in 1945 by Dr. Walter Blount,this method is known as epiphyseal stapling. Typically epiphysealstapling is more applicable in young pediatric patients and adolescentswith active growth plates. A staple is placed on the convex side of anangular deformity. Since the bone is free to grow on the concave side ofthe deformity, the bone tends to grow on the unstapled side, causing thebone to realign over time. Once the bone is aligned, the constrainingimplants are typically removed.

As long as the growth plate is not disturbed, this type of interventionis generally successful. However, the procedure must be done during thetime that the bone is still growing, and the physiodynamics of thephysis (growth plate) must not be disturbed. With proper preoperativeplanning and placement of the implants, the surgeon can use the implantsto slowly guide the bone back into alignment.

The implants currently used in epiphyseal stapling procedures aregenerally U-shaped, rigid staples. The general design has essentiallyremained the same as those devised by Blount in the 1940's. Since theseimplants are rigid, they act as three-dimensional constraintsprohibiting expansion of the growth plate. They are not designed toallow flexibility or rotation of the staple legs with the bone sectionsas the bone is realigned. Due to the constraints of these stapleimplants, the planning associated with the placement of the implants isoverly complicated. Consequently, the surgeon must not only determinewhere to position the implant across the physis, but also must accountfor the added variables of implant stiffness, implant strength andbone-implant interface rupture.

The force associated with bone growth causes bending of these implantsproportionate to their stiffness. Depending on the strength of theimplant, these loads could eventually cause the implants to fractureunder the force of bone realignment. This can make them difficult orimpossible to remove. These same forces can also cause the implants todeform, weakening the bone-to-implant interface. This weakening mayresult in migration of the implant out of the bone, risking damage tothe adjacent soft tissues and failure of the procedure.

SUMMARY OF THE INVENTION

The invention relates to an orthopedic bone alignment implant systemthat includes a guide wire, a link and bone fasteners. The guide wireserves to locate the growth plate under fluoroscopic guidance. The bonefasteners and the link function together as a tether between bonesegments on opposite sides of the physis. As the bone physis generatesnew physeal tissue, the bone alignment implant tethers between engagerson the bone segments. This tethering principle guides the alignment ofthe bone as it grows.

Although applicable in various orthopedic procedures involving fracturefixation, the bone alignment implant is also applicable to thecorrection of angular deformities in long bones in which the physis isstill active.

The distal end of the guide wire is used to locate the physis. Once itstip is placed in the physis, it is driven partly into the physis tofunction as a temporary guide for the link. The delivery of the implantover the guide wire assures that the link is properly placed with thebone fasteners on opposite sides of the physis. This will minimize thechance of damaging the physis throughout bone realignment. The link isthen placed over the guide wire and oriented such that openings throughthe link for the bone fasteners are on either side of the physis. Forpure angular correction, these openings would be collinear with the longaxis of the bone; for rotational correction, they would be oblique toits axis.

The bone fasteners are then placed through the openings in the link andinto the bone, connecting the sections of bone on opposite sides of thephysis with the implant. Alternatively, guide pins can be used to helpalign canullated fasteners.

The implant is designed such that it partially constrains the volume ofthe bone growth on the side of the physis that it is placed. The implantguides the growth of new bone at the physis such that the growthdirection and resulting alignment is controlled. The implant limits thesemi-longitudinal translation of the bone fasteners yet allows for thebone fasteners to freely rotate with the bone segments as the angular ortorsional deformity is straightened.

In some embodiments of this invention, both the link and the fastenersare rigid, but the connection between them allows for relative movementof the fasteners. In other embodiments the link is flexible allowing thefasteners to move with the bone sections. In other embodiments, thefasteners have flexible shafts allowing only the bone engager of thefasteners to move with the bone sections. In still other embodiments,both the link and the shafts of the fasteners are flexible, allowingmovement of the bone sections.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present invention will now be discussed withreference to the appended drawings. It is appreciated that thesedrawings depict only typical embodiments of the invention and aretherefore not to be considered limiting of its scope.

FIG. 1 is an anterior view of the knee showing a genu valgum deformity(knee knocking) in the femur and the insertion of a guide wireapproximately parallel to the physis;

FIG. 2 is a sagittal view of that described in FIG. 1 showing theplacement of the guide wire in the physis;

FIG. 3 is anterior view of the knee showing the placement of a link anddrill guide over the guide wire and the use of the guide to place twoguide pins for fasteners on opposite sides of the physis;

FIG. 4 is a sagittal view of the placement of the link described in FIG.3 showing the position of the two guide pins on opposite sides of thephysis;

FIG. 5 is an alternative method of applying the link over the guide wirein which the link is placed first, then the fasteners are placed throughthe openings in the link;

FIG. 6 is a sagittal view of the link placement also shown in FIG. 5;

FIG. 6A is a top plan view of the link shown in FIG. 6;

FIG. 7 is an anterior view showing an alternative method of drilling ofholes in the bone over the guide pins to prepare the bone for thefasteners;

FIG. 8 is a anterior view of the link showing the placement of thefasteners through the link and into the bone segments;

FIG. 9 is a sagittal view of the fasteners and link described in FIG. 8;

FIG. 10 is an anterior view as seen after the physeal tissue has grownand the bone alignment implant assembly has been reoriented as the boneis realigned;

FIG. 11 is sagittal view of the bone alignment implant placed on arotational deformity;

FIG. 12 is the same sagittal view described in FIG. 12 after therotational deformity has been corrected;

FIG. 13 is a perspective view of a threaded fastener;

FIG. 14 is perspective view of a barbed fastener;

FIG. 15 is perspective view of an alternative embodiment of the bonealignment implant with rigid link and fasteners, with joints allowingrestricted movement between them;

FIG. 16 is a perspective view of an alternative embodiment of the bonealignment implant showing a flexible midsection of the link with rigidmaterial surrounding the openings;

FIG. 17 is a perspective view of an alternative embodiment of the bonealignment implant showing a flexible midsection of the link made from aseparate flexible member with rigid material surrounding the openings;

FIG. 18 is a perspective view of an alternative embodiment of the bonealignment implant showing flexible woven material throughout the body ofthe link with reinforcement grommets surrounding the openings;

FIG. 19 is a perspective view of an alternative embodiment of the bonealignment implant showing the link made from a flexible band ofmaterial;

FIG. 20 is a perspective view of an alternative embodiment of the bonealignment implant showing the link made from a flexible ring of braidedmaterial that is joined in the midsection, forming two openings;

FIG. 21 is a side view of an alternative embodiment of the bonealignment implant showing a bone fasteners that have flexible shaftsections;

FIG. 22 is a side view of an alternative embodiment of the bonealignment implant showing two barbed bone fasteners attached to aflexible link; and

FIG. 23 is a side view of an alternative embodiment of the bonealignment implant showing one barbed bone fastener and one threaded bonefastener connected to a flexible link.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to FIG. 1, a schematic anterior view of the human knee jointis depicted in which a distal femur 10 is proximal to a proximal tibia 5and a proximal fibula 6. A distal femoral physis 1, or growth plate,separates a distal epiphyseal section 3 from a proximal metaphysealsection 2 of the distal femur 10. Likewise a proximal tibial physis 1′separates a proximal epiphyseal section 3′ from a metaphyseal section 2′of the proximal tibia 5 and a proximal fibula physis 1″ separates aproximal epiphyseal section 3″ of a proximal fibula 6 from a metaphysealsection 2″ of the proximal fibula 6. Although the invention describedherein is adaptable to nearly all of the long bones in the body, onlythe example of correcting one type of an angular deformity in the distalfemur will be described in detail. The principles described herein canbe adapted to other deformities and other bones such as the tibia,fibula, humerus, radius and ulna.

By example, an angular deformity 4 in the femur 10 known as genu valgumor knock-knee is shown in FIG. 1. The angular deformity 4 is the anglebetween a pretreatment longitudinal axis 12 of the femur 10 and a posttreatment projected longitudinal axis 13 of the femur 10. A bonealignment implant will be placed on the medial side of the femur 10. Inthis case, the medial side of the femur 10 is curved in a convex arc.Hence, this side of the deformity is called a convex side 16 because theangular deformity 4 bends the femur 10 in a curve that is angled awayfrom or convex with respect to the medial side. A concave side 17 is onthe opposite side of the femur 10. Likewise, the angular deformity 4 isangled towards the concave side 17.

A guide wire 8, as shown in FIG. 1, is used to locate the physis andguide the bone alignment implant to the surgical site. The guide wire 8comprises a long axis 11, a distal section 9 that is shaped to fit intothe physeal tissue, and a periphery 14 that is typically a constant sizeand shape. In this case, the shape of the guide wire 8 along the longaxis 11 is essentially cylindrical so the shape of the periphery 14 isround and does not change except for in the distal section 9. However,the periphery 14 can be a variable cross-section that changes shape orsize along the length of the long axis 11.

In this example, the long axis 11 of the guide wire 8 is placed into andapproximately parallel with the physis 1 and is aligned approximately inthe same plane as the angular deformity 4. As shown in FIG. 1, thedistal section 9 of the guide wire 8 is partly inserted into the physis1. Since the cartilaginous physis 1 is of less density than thesurrounding bone, the surgeon can either poke the distal section of theguide wire 8 into the bone until the physis 1 is located, or the surgeoncan use fluoroscopic x-ray (not shown) or other bone density detectionmeans (not shown) to determine the location of the physis 1 relative tothe distal section of the guide wire 8 to place the guide wire 8 in adirection that is approximately parallel with the physis 1.

FIG. 2 is a sagittal view approximately perpendicular to the anteriorview described in FIG. 1. For reference, a patella 7 is shown on theanterior side of the femur 10 and tibia 5. For clarity, in this examplethe guide wire 8 is straight and has a constant round outer periphery14. Consequently, only the outer periphery 14 of the guide wire 8 isshown and appears as a circle in FIG. 2. FIG. 2 shows the placement ofthe guide wire 8 in the physis between the femoral metaphyseal section 2and the distal femoral epiphyseal section 3. This is the preferredplacement of the guide wire 8. The guidewire 8 is used to locate an areain the physis that will eventually be bridged by the bone alignmentimplant 9 that will tether between two sections of the bone. In FIG. 2,the two sections of bone that will be tethered by the bone alignmentimplant 9 are the distal femoral proximal epiphyseal section 3 and thefemoral metaphyseal section 2.

FIG. 3 is an anterior view of the knee showing the placement of a link30 and a guide 20 over the guide wire 8. The guide 20 is used to place afirst guide pin 40 and a second guide pin 50 on opposite sides of thephysis 1. The link 30 has an outer periphery 34 that defines the outermaterial bounds of the link 30, a bone side 37 that is the side of thelink that is placed against the bone, a first opening 31 and a secondopening 32.

First, the guide 20 and link 30 are placed over the guide wire 8 byguiding the guide wire 8 over a guide opening 33 in the link 30 and theguide hole 23 in the guide 20. Then the first guide pin 40 is driventhrough a first hole 21 in the guide 20 and through the first opening 31in the link 30 into the metaphyseal bone 2, and the second guide pin 50is driven through a second hole 22 in the guide 20 and the secondopening 32 in the link 30 into the distal epiphyseal section 3. Once thefirst guide pin 40 and the second guide pin 50 are placed, the guide 20is removed.

FIG. 4 is a sagittal view of the placement of the link 30 described inFIG. 3. The position of the first guide pin 40 is through the firstopening 31 in the link 30. The position of the second guide pin 50 isthough the second opening 32 in the link 30. The guide pin 40 and guidepin 50 are on opposite sides of physis 1. Likewise, the first opening 31and the second opening 32 are on opposite sides of the physis 1.

FIG. 5 is an anterior view showing an alternative embodiment of the link30 placed on the medial femur 10. In this embodiment, a first set ofspikes 35 and a second set of spikes 36 on the bone side 37 of the link30 help to keep the link 30 in place prior to the placement of a firstbone fastener 70 and a second bone fastener 80. The first set of spikes35 is positioned near the first opening 31 and the second set of spikes36 is positioned near the second opening 32 in the link 30. Hence, asthe link 30 is placed across the physis 1, the first set of spikes 35contacts the metaphyseal section 2 and the second set of spikes 36contacts the epiphyseal section 3. In this embodiment, the first bonefastener 70 is placed though the first opening 31 in the link 30 theninto the metaphyseal section 2 and the second bone fastener 80 is placedthrough the second opening 32 in the link 30 then into the epiphysealsection 3.

FIG. 6 is a sagittal view of the link 30 on the femur 10 showing thelocation of the first set of spikes 35 near the first opening 31 on themetaphyseal section 2 side of the physis 1 and the location of thesecond set of spikes near the second opening 32 on the epiphysealsection 3 side of the physis 1.

As shown in FIG. 6A, link 30 can further be defined as having a topsurface 150 that is opposite the bottom surface 37. Bottom surface 37was also previously referenced as bone side 37 in FIG. 3. Both bottomsurface 37 and top surface 150 extend between a first side edge 152 andan opposing second side edge 154. Likewise, both bottom surface 37 andtop surface 150 longitudinally extend between a first end 156 and anopposing second end 158. A first recess 162 is centrally formed on firstside edge 152 while a second recess 164 is centrally formed on secondside edge 154.

In the embodiment depicted, guide opening 33 is centrally disposedbetween first opening 31 and second opening 32 with guide opening 33being smaller than openings 31 and 32. Each of openings 31, 32, and 33are aligned along a central longitudinal axis 160 that extends betweenfirst end 156 and second end 158. Recesses 162 and 164 can be positionedon opposing sides of guide opening 33 such that a linear line 166extending between recesses 162 and 164 intersect guide opening 33. Thelength of linear line 166 extending between recesses 162 and 164 is afirst width of link 30. Linear line 166 is shown in the presentembodiment as extending orthogonal to longitudinal axis 160.

Link 30 can also be formed so that a linear line 168 can extend betweenside edges 152 and 154 so as to intersect with first opening 31. Line168 is shown extending orthogonal to longitudinal axis 160 and measuresa second width of link 30. Because of recesses 162 and 164, the firstwidth is smaller than the second width. A linear line 170 can similarlyextend between side edges 152 and 154 so as to intersect with secondopening 32. Line 170 is shown extending orthogonal to longitudinal axis160 and measures a third width of link 30. The first width of link 30 issmaller than the than the third width.

FIG. 7 is an anterior view of the placement of the link 30, first guidepin 40, and second guide pin 50 as previously described in the sagittalview shown in FIG. 4. FIG. 7 also shows a bone preparation tool 60 thatcan be used to prepare a bore 28 in the bone prior to the first fastener70 or second fastener 80 placements. The bone preparation tool 60 can bea drill, tap, rasp, reamer, awl or any tool used to prepare a bore inbone tissue for a fastener. The bone preparation tool 60 is used toprepare a bore 28 on the bone near the second opening in the epiphysealsection 3 for the second fastener 80. A bone preparation tool 60 canalso be used to prepare the bone in the metaphyseal section 2 for thefirst fastener 70. In the case of the example shown in FIG. 7, the bonepreparation tool 60 is placed over the second guide pin 50, through thesecond opening 32, and into the epiphyseal section 3. However, the bonepreparation tool 60 can also be placed directly through the secondopening 32 without the guidance of the second guide pin 50. The bonepreparation tool 60 is used if needed to prepare the bone to receive thefirst fastener 70 and second fastener 80. Once the bone is prepared, thebone preparation tool 60 is removed from the surgical site.

The first fastener 70 is then placed over the first guide pin 40,through the first opening 31, and into the metaphyseal section 2. Thesecond fastener 80 is placed over the second guide pin 50, through thesecond opening 32 and into the epiphyseal section 3. If the first guidepin 40 and second guide pin 50 are not used, the first fastener 70 issimply driven through the first opening 31 and the second fastener 80 issimply driven though the second opening 32 without the aid of the guidepins 40 and 50.

FIG. 8 is an anterior view showing the position of a bone alignmentimplant 15 on the convex side 16 of the angular deformity 4. The bonealignment implant 15 comprises the link 30, the first fastener 70, andthe second fastener 80. The bone alignment implant 15 functions as atether connecting the metaphyseal section 2 and the epiphyseal section3. The first fastener 70 and the second fastener 80 are placed onopposite sides of the physis 1. As the physis 1 generates new physealtissue 90, the physeal tissue 90 will fill in between the metaphysealsection 2 and the epiphyseal section 3 in the space subjected to theleast resistance. The bone alignment implant 15 restricts thelongitudinal movement between the epiphyseal section 3 and themetaphyseal section 3 on the convex side 16 of the angular deformity 4.

FIG. 9 shows the sagittal view of that described for FIG. 8. The bonealignment implant 15 functioning as a tether restricting thelongitudinal movement between the epiphyseal section 3 and themetaphyseal section 2.

As shown in FIG. 10, in a patient with an active physis, the newlygenerated physeal tissue 90 fills in more on the side of the bone thatis not tethered by the bone alignment implant 15. Hence, a net gain 95of physeal tissue 90 forces the bone to align in the direction of anangular correction 97.

Select embodiments of the bone alignment implant 15 comprise the firstfastener 70 having a first engager 75, the second fastener 80 having asecond engager 85 and the link 30. The link 30, the first fastener 70and the second fastener 80 function together as tethers between a firstengager 75 on the first fastener 70 and a second engager 85 on thesecond fastener 80, guiding movement between the epiphyseal section 3and metaphyseal section 2 of bone.

FIG. 11 and FIG. 12 show an example of using the bone alignment implantto correct a torsional abnormality between the metaphyseal section 2 andthe epiphyseal section 3. The link 30 is placed across the physis 1 atan angle 18 that is related to the amount of torsional deformity betweenthe bone sections 2 and 3. As the physis 1 generates new physeal tissue90, the bone alignment implant 15 guides the direction of growth of thebone to allow a torsional correction 98 of the bone alignment.

Different fastening device designs that are well known in the art can befunctional as fasteners 70 and 80. The basic common elements of thefasteners 70 and 80 are seen in the example of a threaded fastener 100in shown in FIG. 13 and a barbed fastener 120 shown in FIG. 14.

The threaded fastener 100, and the barbed fastener 120 both have a head73 comprising a head diameter 74, a drive feature 72 and a headunderside 71. The drive feature in the threaded fastener 100 is aninternal female hex drive feature 102. The drive feature in the barbedfastener 120 is an external male drive feature 122. The shape of theunderside 71 of the barbed fastener 120 is a chamfer cut 124 and theunderside of the threaded fastener 100 is rounded cut 104. The underside71 shape of both the threaded fastener 100 and the barbed fastener 120examples are dimensioned to mate with shapes of the first opening 31 andthe second opening 32 in the link 30.

Directly adjacent to the head 72 on both threaded fastener 100 and thebarbed fastener 120 is a fastener shaft 79 with a shaft diameter 76.Protruding from the shaft 79 is the aforementioned engager 75 with afixation outer diameter 77. This fixation diameter varies depending onthe bone that is being treated and the size of the patient. Typicallythis diameter is from 1 mm to 10 mm. The shaft diameter 76 can be anundercut shaft 125, as shown in the barbed fastener 120, with a diameter75 smaller than the fixation outer diameter 77. The shaft diameter canalso be a run out shaft 105 as shown in the threaded fastener 100 with adiameter 76 larger than or equal to the fixation diameter 77. In eithercase, the shaft diameter 76 is smaller than the head diameter 74. Thisallows fasteners 70 and 80 to be captured and not pass completelythrough the openings 31 and 32 in the link 30.

In the case of the threaded fastener 100, the engager 75 comprises atleast one helical thread form 103. Although the example of a unitarycontinuous helical thread 103 is shown, it is understood that multiplelead helical threads, discontinuous helical threads, variable pitchhelical threads, variable outside diameter helical threads,thread-forming self-tapping, thread-cutting self-tapping, and variableroot diameter helical threads can be interchanged and combined to forman optimized engager 75 on the threaded fastener 100. The engager 75 onthe barbed fastener 120 is shown as a uniform pattern of connectedtruncated conical sections 123. However, it is understood that differentbarbed fastener designs known in the art such as superelastic wire arcs,deformable barbs, radially expandable barbs, and barbs with non-circularcross-sections can be interchanged and combined to form a optimizedengager 75 on the barbed fastener 120.

Protruding from the engager 75 at the distal end of both the threadedfastener 100 and the barbed fastener 120 is a fastener tip 78. Thefastener tip 78 can either be a smooth conical tip 126 as shown in thebarbed fastener 120, or a cutting tip 106 as shown on the threadedfastener 100. Although a cutting flute tip is shown as the cutting tip106 on the threaded fastener, other cutting tips designs includinggimble and spade tips can be used.

In the example of the barbed fastener 120, a canulation bore 128 passesthough the head 71, the shaft 79, the engager 75, and the tip 78. Thiscanulation bore 128 allows placement of the fasteners 70 and 80 over theguide pins 40 and 50. Although not shown on the example of the threadedfastener 100 in FIG. 13, it is understood that the fasteners 70 and 80,regardless of their other features, can either be of the cannulateddesign shown in the barbed fastener 120 example or a non-cannulateddesign as shown in the threaded fastener 100 example.

Fasteners 70 and 80 can be made in a variety of different ways using avariety of one or more different materials. By way of example and not bylimitation, Fasteners 70 and 80 can be made from medical gradebiodegradable or non-biodegradable materials. Examples of biodegradablematerials include biodegradable ceramics, biological materials, such asbone or collagen, and homopolymers and copolymers of lactide, glycolide,trimethylene carbonate, caprolactone, and p-dioxanone and blends orother combinations thereof and equivalents thereof. Examples ofnon-biodegradable materials include metals such as stainless steel,titanium, Nitinol, cobalt, alloys thereof, and equivalents thereof andpolymeric materials such as non-biodegradable polyesters, polyamides,polyolefins, polyurethanes, and polyacetals and equivalents thereof.

All the design elements of the threaded fastener 100 and barbed fastener120 are interchangeable. Hence either of the fasteners 70 and 80 cancomprise of any combination of the design elements described for thethreaded fastener 100 and the barbed fastener 120. By way of oneexample, the first fastener 70 can be made from a bioabsorbablecopolymer of lactide and glycolide and structurally comprise an externalmale drive feature 122, a run out shaft 105, a multiple-lead,non-continuous helically threaded engager 75, with a cutting flute tip106 and a continuous emulation 128. Likewise the second fastener 80 canbe made from a different combination of the features used to describethe threaded fastener 100 and the barbed fastener 120.

Although the examples of barbed connected truncated conical sections 123and helical thread forms 103 are shown by example to represent the boneengager 75, it is understood that other means of engaging bone can beused for the engager 75. These means include nails, radially expandinganchors, pressfits, tapers, hooks, surfaces textured for biologicalingrowth, adhesives, glues, cements, hydroxyapitite coated engagers,calcium phosphate coated engagers, and engagers with tissue engineeredbiological interfaces. Such means are known in the art and can be usedas alternative bone engagement means for the first bone engager 75 onthe first fastener 70 or the second bone engager 85 on the secondfastener 80.

Different embodiments of the bone alignment implant 15 invention allowfor different means of relative movement between the two bone sections 2and 3. Nine embodiments of the bone alignment implant 15 are shown inFIG. 15 through FIG. 23. These embodiments are labeled 15A through 15I.

In a rigid-bodies embodiment 15A shown in FIG. 15, both the link 30 andthe fasteners 70 and 80 are rigid, but a first connection 131 and asecond connection 132 between each of them allows for relative movementbetween the link 30 and the fasteners 70 and 80 resulting in relativemovement between the bone sections 2 and 3. In embodiments 15B, 15C, and15D of this invention shown in FIG. 16, FIG. 17 and FIG. 18, the link 30is deformable allowing the fasteners 70 and 80 to move with the bonesections 2 and 3. In embodiments 15E and 15F shown in FIG. 19 and FIG.20, the connections between the link 30 and the fasteners 70 and 80along with the deformable link 30 allow the fasteners 70 and 80 to movewith the bone sections 2 and 3. In an embodiment 15G shown in FIG. 21,the fasteners 70 and 80 are deformable allowing movement of the bonesections 2 and 3. In embodiments 15H and 15I shown in FIG. 22 and FIG.23, the fasteners 70 and 80 are fixed to a flexible link 30.

A rigid-bodies embodiment 15A of the bone alignment implant 15 is shownin FIG. 15. In the rigid-bodies embodiment 15A, the link 30 is a rigidlink 130. In the rigid bodies embodiment 15A, the first fastener 70 isfree to rotate about its axis or tilt in a first tilt direction 60 or asecond tilt direction 61 and is partially constrained to move in alongitudinal direction 62 by the confines of the size of the firstopening 31 and the first shaft diameter 77, and partially constrained tomove in the axial direction by the confines of the size of the firstopening and the diameter 74 of the head 73 of the first fastener 70. Thefirst opening 31 is larger in the longitudinal direction 62 than is theshaft diameter 77 of the first fastener 70. This allows for relativemovement at the first joint 131 in a combination of tilt in the firstdirection 60, tilt in the second direction 61, and translation in theaxial direction 63.

Similar tilt and translation is achieved between the second fastener 80and the link 30 at the second joint 132. The second fastener 80 is alsofree to rotate or tilt in a first tilt direction 60′ or a second tiltdirection 61′ and is partially constrained to move in a longitudinaldirection 62′ by the confines of the size of the second opening 32 andthe shaft diameter of the second fastener 80. The second opening 31 islarger in the longitudinal direction 62′ than is the shaft diameter ofthe second fastener 70. This allows for relative movement at the secondjoint 132 in a combination of tilt in the first direction 60′ and tiltin the second direction 61′ and limited translation in the axialdirection 63′.

The combination of relative movement between the first joint and thesecond joint allows for relative movement between the bone sections 2and 3 when the rigid bodies embodiment 15A of the bone alignment implant15 is clinically applied across an active physis 1.

A flexible link embodiment 15B of the bone alignment implant 15 is shownin FIG. 16. In the deformable link embodiment 15B, the link 30 isrepresented by a deformable link 230 that allows deformation of thesection 2 and 4 as the physis 1 grows in a first bending direction 64and a second bending direction 65. However, the maximum length betweenthe first opening 31 and the second opening 32 of the deformable link230 limits the longitudinal displacement 62 between the head 73 of thefirst fastener 70 and the longitudinal displacement 62′ between the head83 of the second fastener 80. Since the heads 73 and 83 are coupled tothe respective bone engagers 75 and 85, and the bone engagers 75 and 85are implanted into the respective bone segments 2 and 3, the maximumlongitudinal displacement of the bone segments 2 and 3 is limited by thedeformed length between the first opening 31 and second opening 32 ofthe link 30, and the flexibility and length of the fasteners 70 and 80.

Also shown in FIG. 16 is a material differential area 38 on the link 30.The material differential area 38 is an area on the link 30 wherematerial is either added to the link 30 or removed from the link 30 inrelationship to the desired mechanical properties of a central section39 of the link 30. The central section 39 is made stiffer by addingmaterial to the material differential area 38.

The central section 39 is made more flexible by removing material fromthe material differential area 38. Similarly the central section 39 ismade stiffer by holding all other variables constant and decreasing thesize of the guide opening 33. The central section 39 is made moreflexible by increasing the size of the guide opening 33. Hence thedesired stiffness or flexibility of the link 30 is regulated by therelative size of the material removed or added at the materialdifferential areas 37 and 38 and the relative size of the guide opening33 with respect to the outer periphery 34 in the central section 39 ofthe link 30.

It is also understood that the relative stiffness and strength of thelink 30 and structural elements such as the central section 39 isdependent on the material from which it is made. The link 30 andstructural elements such as the central section 39 therein can be madein a variety of different ways using one or more of a variety ofdifferent materials. By way of example and not by limitation, thecentral section 39 can be made from medical grade biodegradable ornon-biodegradable materials. Examples of biodegradable materials includebiodegradable ceramics, biological materials, such as bone or collagen,and homopolymers and copolymers of lactide, glycolide, trimethylenecarbonate, caprolactone, and p-dioxanone and blends or othercombinations thereof and equivalents thereof. Examples ofnon-biodegradable materials include metals such as titanium alloys,zirconium alloys, cobalt chromium alloys, stainless steel alloys,Nitinol alloys, or combinations thereof, and equivalents thereof andpolymeric materials such as non-biodegradable polyesters, polyamides,polyolefins, polyurethanes, and polyacetals and equivalents thereof.

FIG. 17 shows a flexible cable embodiment 15C of the bone alignmentimplant 15. The flexible cable embodiment 15C comprises a flexible cablelink 330 joined to the first fastener 70 by a first eyelet 306 on thefirst side 310 and joined to the second link 80 by a second eyelet 307on the second side 311. The first eyelet 306 has a first opening 331through which the first fastener 70 passes. The second eyelet 307 has asecond opening 332 through which the second fastener 80 passes. Aflexible member 339 connects the first eyelet 306 to the second eyelet307. The flexible member 339 allows relative movement between the firsteyelet 306 and the second eyelet 307, except the longitudinaldisplacement 62 and 62′ is limited by the length between the firstopening 331 and the second opening 332. This is proportional to thelength of the flexible member 339.

The flexible member 339 is connected to the first eyelet 306 and thesecond eyelet 307 by means of joined connections 318 and 319. Thesejoined connections 318 and 319 are shown as crimped connections in thisexample. However, the flexible member 339 can be joined to the link 30by other means such as insert molding, welding, soldering, penning,pressfitting, cementing, threading, or gluing them together.

FIG. 18 shows a flexible fabric embodiment 15D of the bone alignmentimplant 15. The flexible fabric embodiment 15D comprises a flexiblefabric link 430 joined to the first fastener and the second fastener 80.The flexible fabric link 430 comprises a first grommet 406 on a firstside 410 and joined to the second link 80 by a second grommet 407 on asecond side 411. The first grommet 406 has a first opening 431 throughwhich the first fastener 70 passes. The second grommet 407 has a secondopening 432 through which the second fastener 80 passes. A flexiblefabric 439 connects the first grommet 406 to the second grommet 407. Theflexible fabric 439 allows relative movement between the first grommet406 and the second grommet 407, except the longitudinal displacement 62is limited by the length between the first opening 431 and the secondopening 432. A guide hole grommet 433 may be employed to reinforce theguide pin opening 33.

The grommets function as reinforcement structures that prevent theflexible fabric from being damaged by the fasteners 70 and 80. Thegrommets can be made from medical grade biodegradable ornon-biodegradable materials. Examples of materials from which thegrommet can be made are similar to those bioabsorbable andnon-biodegradable materials listed as possible materials for thefasteners 70 and 80.

The flexible fabric 439 comprises woven or matted fibers of spun medicalgrade biodegradable or non-biodegradable materials. A wide variety ofmaterials may be used to make the flexible fabric 439. For example,wire, fibers, filaments and yarns made therefrom may be woven, knittedor matted into fabrics. In addition, even non-woven structures, such asfelts or similar materials, may be employed. Thus, for instance,nonabsorbable fabric made from synthetic biocompatible nonabsorbablepolymer yarns, made from polytetrafluorethylenes, polyesters, nylons,polyamides, polyolefins, polyurethanes, polyacetals and acrylic yarns,may be conveniently employed. Similarly absorbable fabric made fromabsorbable polymers such as homopolymers and copolymers of lactide,glycolide, trimethylene carbonate, caprolactone, and p-dioxanone andblends or other combinations thereof and equivalents thereof may beemployed. Examples of non-biodegradable non-polymeric materials fromwhich the flexible fabric can be made include metals such as stainlesssteel, titanium, Nitinol, cobalt, alloys thereof, and equivalentsthereof.

A band embodiment 15E is shown in FIG. 19 in which a band 530 that is acontinuous loop or band of material that functions as the link 30. Theband embodiment 15E allows both movement at the first joint 131 andsecond joint 132 and allows deformation within the link 30. The shafts79 of the first fastener 70 and second fastener 80 are both positionedin the inside 531 of the band 530. The band can be either a fabric bandmade from the same materials described for the flexible fabric 439 ofthe flexible fabric embodiment 15D, or the band 530 can be a unitary,continuous loop of a given biocompatible material such as abioabsorbable polymer, non-biodegradable polymer, metal, ceramic,composite, glass, or biologic material.

In the band embodiment 15E, the band 530 tethers between the head 73 ofthe first fastener 70 and the head 83 of the second fastener as thephyseal tissue 90 generates and the bone in aligned. One advantage ofthe band embodiment 15E is that after the desired alignment is obtained,the band 530 can be cut and removed without removing the fasteners 70and 80. Furthermore, as with all of the embodiments of the bonealignment device 15A, 15B, 15C, 15D, 15F, 15G, 15H and 15I, thefasteners 70 and 80 can be made from a biodegradable material and leftin place to degrade.

A crimped band embodiment 15F of the bone alignment device 15 is shownin FIG. 20. The crimped band embodiment 15F is similar to the bandembodiment 15E in that it allows both movement at the first joint 131and second joint 132. The crimped band embodiment 15F comprises acrimped band link 630 that comprises a band 632 that loops around thehead 73 of the first fastener 70 and the head 83 of the second fastener80. However, the link 30 in the crimped band embodiment 15F has anadditional ferrule feature 631 comprising a loop of deformable materialthat brings a first side 634 and a second side 635 of the band togetherforming the first opening 32 and the second opening 32. A bore 633 inthe midsection of the ferrule 631 passes through the crimped band link630 to form the aforementioned guide pin hole 33.

As with the band embodiment 15E, an advantage of the band embodiment 15Eis that after the desired alignment is obtained, the band 632 can besevered across the boundaries of the first opening 31 and the boundariesof the second opening 32. This provides a means for the crimped bandlink 630 to be removed without removing the fasteners 70 and 80.

A deformable fastener embodiment 15G is shown in FIG. 21. The deformablefastener shaft embodiment 15G comprises a first deformable fastener 770with a deformable shaft 776, a link 30 and a second fastener 80. Thesecond fastener 80 may also have a deformable shaft 786 as shown in thedeformable fastener embodiment 15G. However, it may also have anondeformable shaft. The second fastener 80 may also be in the design ormaterial of any of the combinations of aforementioned threaded fasters100 or barbed fasteners 120. Likewise, the second fastener 80 can have aflexible shaft 786, as shown in the example of the deformable fastenerembodiment 15G in FIG. 21, and the first fastener 70 can be in thedesign or material of any of the combinations of aforementioned threadedfasters 100 or barbed fasteners 120.

The flexibility of the flexible shaft 776 and 786 of the fasteners 70and 80 can be simply a result of the material selection of the flexibleshaft 776 and 786, or can be the result of a design that allows forflexibility of the shaft. For example, the flexible shaft 776 and 786can be manufactured from a material such as the aforementionedbiocompatible polymeric materials or superelastic metallic materialssuch as Nitinol that would deform under the loads associated with bonealignment. The flexible shafts 776 and 786 could also be manufacturedfrom biocompatible materials typically not considered to be highlyelastic such as stainless steel, titanium, zirconium, cobalt chrome andassociated alloys thereof, and shaped in the form of a flexible membersuch as cable, suture, mesh, fabric, braided multifilament strand,circumferentially grooved flexible shaft, filament, and yarn.

Connections 778 and 788 between the flexible shafts 776 and 786 and theassociated engagers 775 and 780 of the fasteners 70 and 80 can beunitary and continuous, as is typically the case for fasteners 70 and 80made entirely from the aforementioned biocompatible polymeric materialsand superelastic metallic materials. The connections 778 and 788 canalso be joined connections as is the case for flexible shafts 776 and786 made from flexible members. Although the example of a pressfitconnection is shown as the means of the connections 778 and 788 in thedeformable fastener embodiment 15G shown in FIG. 21, these joinedconnections 778 and 788 can be crimped, welded, insert molded, soldered,penned, pressfit, cemented, threaded, or glued together.

Heads 773 and 783 are connected to the respective flexible shafts 776and 786 by respective head connections 779 and 789. These headconnections 779 and 789 can also be unitary and continuous, as again istypically the case of fasteners 70 and 80 made entirely from theaforementioned biocompatible polymeric materials and superelasticmetallic materials. The head connections 779 and 789 can also be joinedconnections, as is the case for flexible shafts 776 and 786 made fromflexible members. Although the example of a pressfit connection is themeans of the connections 779 and 789 in the deformable fastenerembodiment 15G shown in FIG. 21, these joined connections 779 and 789can also be crimped, insert molded, welded, soldered, penned, pressfit,cemented, threaded, or glued together.

Embodiments of the bone alignment implant 15 are shown in FIGS. 22 and23 in which the first fastener 70 and second fastener 80 are fixedlyjoined to the link 30 that is flexible.

A paired fastener embodiment 15H is shown in FIG. 22 in which similardesigns of paired fasteners 870 and 880 are fixedly joined to a flexiblelink 830 by means of joined connections 831 and 832. These joinedconnections 831 and 832 are shown as insert molded connections in thisexample in which the link is formed within the fastener by means ofmolding the molded fasteners 870 and 880 around the flexible link 830.However, the pair fasteners 870 and 880 can be joined to the link 830 byother means such as crimping, welding, soldering, penning, pressfitting,cementing, threading, or gluing.

In the paired fastener embodiment 15H, the first paired fastener 870 andthe second paired fastener 880 are shown in FIG. 22 as barbed stylefasteners similar to the aforementioned barbed fastener 120. However,the paired fasteners 870 and 880 can also be similar to theaforementioned threaded fastener 100 or can comprise of any combinationof the design elements described for the threaded fastener 100 and thebarbed fastener 120.

A non-paired fastener embodiment 15I is shown in FIG. 23 in whichdifferent designs of fasteners 970 and 980 are fixedly joined to aflexible link 930 by means of joined connections 931 and 932. Thesejoined connections 931 and 932 are shown as insert molded connections inthis example in which the link is formed within the fastener by means ofmolding the molded fasteners 970 and 980 around the flexible link 930.However, the fasteners 970 and 980 can be joined to the link by othermeans such as crimping, welding, soldering, penning, pressfitting,cementing, threading, or gluing.

While the present invention has been disclosed in its preferred form,the specific embodiments thereof as disclosed and illustrated herein arenot to be considered in a limiting sense as numerous variations arepossible. The invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. No single feature, function, element or property ofthe disclosed embodiments is essential. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. The following claims define certain combinations andsubcombinations that are regarded as novel and non-obvious. Othercombinations and subcombinations of features, functions, elements and/orproperties may be claimed through amendment of the present claims orpresentation of new claims in this or a related application. Suchclaims, whether they are broader, narrower or equal in scope to theoriginal claims, are also regarded as included within the subject matterof applicant's invention. All changes that come within the meaning andrange of equivalency of the claims are to be embraced within theirscope.

1. A bone alignment implant system comprising: an elongated link havinga top surface and an opposing bottom surface that each extend between afirst side edge and an opposing second side edge and which extendbetween a first end and an opposing second end of the link, the linkhaving a first opening extending completely therethrough between the topsurface and the bottom surface at the first end, a second openingextending completely therethrough between the top surface and the bottomsurface at the second end and a guide opening extending completelytherethrough between the top surface and the bottom surface at a centrallocation between the first opening and the second opening, the firstopening, the second opening, and the guide opening being completelyencircled by the link, the guide opening being smaller than the firstopening and the second opening, the link having a central linearlongitudinal axis extending between the first end and the opposingsecond end that intersects with the first opening, the second opening,and the guide opening, the first opening also having a central linearaxis extending therethrough that extends normal to the bottom surface ofthe link, a first recess being centrally formed on the first side edgeand a second recess being centrally formed on the second side edge suchthat a linear line extending orthogonal to the central linearlongitudinal axis can extend between the first recess and the secondrecess and intersect with the guide opening, the first recess and thesecond recess each extending from the top surface to the bottom surfaceof the link; a first bone fastener comprising a first head at one endand a first engager projecting from an opposing end, the first engagerbeing passable though the first opening, and the first head beingprecluded from passing through the first opening; and a second bonefastener comprising a second engager and a second head, the secondengager being passable through the second opening, and the second headbeing precluded from passing through the second opening, wherein neitherthe first engager nor the second engager can pass though the guideopening, wherein the first opening, the second opening, and the guideopening are the only openings formed on the link that extend completelythrough the link and are completely encircled by the link.
 2. The bonealignment implant system as recited in claim 1, wherein the link, thefirst bone fastener, and the second bone fastener are each comprised ofa medical grade material.
 3. The bone alignment implant system asrecited in claim 1, wherein the first engager and the second engagereach have a transverse cross sectional area that is configured so thatneither the first engager nor the second engager can pass through theguide opening.
 4. The bone alignment implant system as recited in claim1, wherein the first head of the first bone fastener can freely rotateand pivot when the first head is seated within the first opening of thelink.
 5. The bone alignment implant system as recited in claim 1,wherein the first engager and the second engager each comprise a helicalthread.
 6. The bone alignment implant system as recited in claim 1,wherein the first bone fastener and the second bone fastener eachcomprise a screw.
 7. The bone alignment implant system as recited inclaim 1, wherein the link has a bottom surface with a plurality ofspikes projecting therefrom.
 8. The bone alignment implant system asrecited in claim 1, further comprising a guide wire having a distal endadapted to slidably pass through the guide opening.
 9. The bonealignment implant system as recited in claim 1, wherein the secondopening also having a central linear axis extending therethrough thatextends normal to the bottom surface of the link.
 10. The bone alignmentimplant system as recited in claim 1, wherein the bottom surface of thelink is smooth with no projections outwardly extending therefrom. 11.The bone alignment implant system as recited in claim 1, wherein the topsurface of the link is complementary to the bottom surface of the link.12. The bone alignment implant system as recited in claim 1, wherein thefirst bone fastener and the second bone fastener each comprise acannulated screw.
 13. An orthopedic bone alignment implant systemcomprising: a link having a top surface and a bottom surface betweenwhich a first opening, a second opening, and a guide opening extend soas to pass completely through the link and so as to be completelyencircled by the link, the guide opening being centrally positionedbetween the first opening and the second opening and being smaller thanthe first opening and the second opening, the top surface and the bottomsurface each extending between a first side edge and an opposing secondside edge which in turn extend between a first end and an opposingsecond end of the link, a first recess being formed on the first sideedge and a second recess being formed on the second side edge such thata linear line can extend between the first recess and the second recessso as to intersect with the guide opening, the first recess and thesecond recess each extending from the top surface to the bottom surfaceof the link, the bottom surface being smooth with no projectionsoutwardly extending therefrom; a first fastener and a second fastenereach having a head at one end and a bone engager projecting from anopposing end; wherein the first and second openings in the link aredimensioned to allow the bone engager of the first fastener and thesecond fastener to pass therethrough and the first opening, the secondopening, and the guide opening are the only openings formed on the linkthat extend completely through the link and are completely encircled bythe link.
 14. The bone alignment implant system as recited in claim 13,wherein the guide opening is configured so that the bone engager of thefirst fastener and the second fastener cannot pass therethrough.
 15. Thebone alignment implant system as recited in claim 13, wherein the firsthead of the first bone fastener can freely rotate and pivot when thefirst head is seated within the first opening of the link.
 16. The bonealignment implant system as recited in claim 13, wherein the firstopening, the second opening, and the guide opening are aligned along alinear longitudinal axis that centrally extends between the first endand the opposing second end of the link, the linear line extendingorthogonal to the linear longitudinal axis.
 17. The bone alignmentimplant system as recited in claim 13, wherein the bone engager of thefirst fastener and the second fastener each comprise a helical thread.18. The bone alignment implant system as recited in claim 13, furthercomprising a guide wire having a distal end adapted to slidably passthrough the guide opening.
 19. The bone alignment implant system asrecited in claim 13, further comprising: the bone engager of the firstfastener is adapted to connect to a epiphyseal section of bone on afirst side of a physis; the bone engager of the second fastener isadapted to connect to a metaphyseal section of bone on a second side ofthe physis; and the link being adapted to span the between theepiphyseal section of bone on the first side of the physis and themetaphyseal section of bone on the second side of the physis.
 20. Thebone alignment implant system as recited in claim 13, wherein the firstopening and the second opening each have a central linear axis extendingtherethrough that extends normal to the bottom surface of the link. 21.The bone alignment implant system as recited in claim 13, wherein thelink has a substantially FIG. 8 configuration.
 22. The bone alignmentimplant system as recited in claim 13, wherein the top surface of thelink is complementary to the bottom surface of the link.
 23. The bonealignment implant system as recited in claim 13, wherein the first bonefastener and the second bone fastener each comprise a cannulated screw.24. An orthopedic bone alignment implant system comprising: a linkhaving a top surface and a bottom surface between which a first opening,a second opening, and a guide opening extend so as to pass completelythrough the link and so as to be completely encircled by the link, theguide opening being centrally positioned between the first opening andthe second opening and being smaller than the first opening and thesecond opening, the top surface and the bottom surface each extendingbetween a first side edge and an opposing second side edge which in turnextend between a first end and an opposing second end of the link, thefirst opening, the second opening, and the guide opening being alignedalong a linear longitudinal axis that centrally extends between thefirst end and the opposing second end of the link, a first recess beingformed on the first side edge and a second recess being formed on thesecond side edge such that a linear line extending orthogonal to thelinear longitudinal axis can extend between the first recess and thesecond recess so as to intersect with the guide opening, the firstrecess and the second recess each extending from the top surface to thebottom surface of the link, the bottom surface being smooth with noprojections outwardly extending therefrom; a first fastener and a secondfastener each having a head at one end and a bone engager projectingfrom an opposing end; wherein the first and second openings in the linkare dimensioned to allow the bone engager of the first fastener and thesecond fastener to pass therethrough and wherein the first opening, thesecond opening, and the guide opening are the only openings formed onthe link that extend completely through the link and are completelyencircled by the link; wherein the guide opening is configured so thatthe bone engager of the first fastener and the second fastener cannotpass therethrough.